Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

In a press statement, Merck said that patients taking cladribine tablets had a nearly 60 percent lower relapse rate than those on placebo pills. The two-year study included 1,326 MS patients who were randomly divided into three groups. Two groups received different doses of cladribine and one group received fake pills.

Patients on cladribine had up to a 60 percent reduced chance of having a relapse compared to patients on placebo. The study was paid for by Merck.

"This is promising news," said Dr. Lee Dunster, head of research for the Multiple Sclerosis Society in the United Kingdom. Dunster was not linked to the Merck study. He said cladribine appeared to be twice as effective as current primary treatments for MS.

Multiple sclerosis is the most common neurological condition affecting young adults. It is the result of damage to myelin, the protective coating on nerve fibers of the central nervous system. When myelin is damaged, that interrupts the brain's messaging system to other parts of the body.

Patients with MS often suffer from fatigue, muscle spams, problems with vision, speech, coordination, and the bladder. Relapses are often unpredictable and there is no known cure.

Current treatments for MS must be given by injections and have varying success rates.

Drug already used to treat leukemia
Cladribine is already used to treat leukemia, but only for short periods of time. Doctors said more information was needed about the potential side effects from taking the drug in the long term, since multiple sclerosis is a lifelong condition.

Known side effects from cladribine include fatigue, an increased chance of infections, and anemia.

Merck has already asked American and European drug regulators to fast-track the drug to the market. In their press statement, Merck said they will submit cladribine for registration in the U.S. and Europe later this year.

Swiss pharmaceutical giant Novartis AG is also working on a pill to treat MS.

Though Merck's study showed that cladribine reduced the relapse rate, Dunster said the real question was whether the drug slowed the disease's progression. He expected that data to be released in the next few months.

"Relapses are not very nice things to have, but we are really looking to slow down the disease," Dunster said. "For patients, it's all about whether or not they will be able to kick around the ball with their kids in a few years."

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